Interpretive Summary: Reproductive hormones, such as the female hormone 17beta-estradiol (E2), have been reported to cause physiological and reproductive disorders in numerous species at low part per trillion (ppt) concentrations, and are present in animal manure contains natural levels of E2 and when applied to soil the persistence and transport of manure-borne E2 were studied by comparing the water transfer of E2 in the soil zone just above the water table (vadose zone) with that of a non-absorbing tracer (fluorobenzoic acid, FBA). This comparison was done using a catch basin (lysimeter) to collect water percolating through the soil installed 2 feet beneath three corn plots that receive swine manure from various sources. An additional control plot was included that had no manure treatment. The duration of the field experiment was from April 10 to August 31, 2003. Soil water transfer was determined using modeling calculations to compare theoretical versus actual percolation of E2 and FBA through the soil profile. On average, lysimeters collected 61% of the expected water transferred E2 and 8% of the FBA. There were frequent detections of E2, i.e. on average 8 detections for the 11 samples taken per lysimeter. The average detected concentration was 21 ng L 1 (ppt). However, 17beta- estradiol was also detected in the first sample set before manure was applied, and in the control plot lysimeters, where no manure was applied. Furthermore, mass recoveries of E2 in all but two of the lysimeters were much greater than 100%. Results indicated that the tracer was transported by rainwater into the soil and percolated down through the soil profile. There was substantial evidence that E2 had accumulated and was present in the vadose zone from prior E2 exposure, and that this E2 was persistent and mobile. The persistence and mobility of the E2 may have resulted from its associations with colloidal materials, such as dissolved organic matter. Furthermore, given the current knowledge of E2 fate and transport in soil the E2 detected was greater and more widespread than would have resulted from our present manure applications.

Technical Abstract:
Reproductive hormones, such as 17beta-estradiol (E2), can cause physiological and reproductive disorders in numerous species at low part per trillion concentrations. The persistence and transport pathways of manure-borne E2 in agricultural soils were determined by comparing the occurrence of E2 in the vadose zone with water transfer and the transport of conservative, non-sorbing fluorobenzoic acid (FBA) tracers. This comparison was done using capillary wick lysimeters installed 0.61 m beneath three corn (Zea mays L.) plots that receive swine (Sus scrofa domesticus) manure from various sources. An additional control plot was included that had no manure treatment. The duration of the field experiment was from April 10 to August 31, 2003. Soil water transfer was calculated using numerical simulations to compare theoretical versus actual percolation in the soil profile. On average, lysimeters collected 61% of the expected percolation and 8% of the FBA. There were frequent detections of E2, where on average there were 8 detections for the 11 samples taken per lysimeter. The average detection concentration was 21 ng L 1 and ranged from 1 to 245 ng L-1. 17beta-estradiol was also detected in the first sample set before manure was applied, and in the control plot lysimeters, where no manure was applied. Furthermore, mass recoveries of E2 in all but two of the lysimeters was much greater than 100%. Results indicated that tracer was advectively transported by precipitated water infiltrating into the soil surface and percolating down through the soil profile. There was substantial evidence for antecedent E2, and that this E2 was persistent and mobile. The persistence and mobility of the E2 may have resulted from its associations with colloidal materials, such as dissolved organic matter. Furthermore, this widespread detection of E2 confounded/overwhelmed any observable effect of manure management on E2 fate and transport.